ALD523D
MULTIFUNCTION 7-DIGIT SERIAL INPUT DISPLAY MODULE CONTROLLER
DUAL SLOPE
A/D 4-PHASE
CONTROLLER
ALD500
CONTROL
LOGIC
FUNCTIONS
SELECTORS
ANALOG
INPUT
SERIAL
BINARY TO
6½
-DIGIT
DECIMAL
CONVERTER
DISPLAY
MODULE
CONTROLLER
CHARACTER
DISPLAY MODULE
EXTERNAL
SERIAL
BINARY
INPUT
SERIAL I/O
INTERFACE
LOGIC
EEPROM
MEMORY
CONTROLLER
EEPROM
PC
ALD523D BLOCK DIAGRAM
PRODUCT FEATURES AND BENEFITS
Up to 7 full digit plus sign (
±
9999999) display
Built-in 21 bit serial binary to
± 6½
digit decimal converter
Compatible with industry standard 1-line x 16 and
2-line x 16 Character Display Modules
User defined 16-alphanumeric character TITLE field
and up to three 8-alphanumeric character UNIT fields
Wide range of alphanumeric display characters
Functional with either LCD or VFD display modules
with column drivers
Designed to operate optionally with ALD500/ALD500R
Precision Analog Signal Processors or directly with serial
inputs
User selected integration time and conversion speed
Cost effective and multipurpose stand alone operation
3 optional modes of operation:
- Mode A, calibrated reference mode
- Mode B, ratiometric mode
- Mode C, display only mode
Support external serial binary input (up to 32 bits)
3-wire serial interface to microprocessors or
microcontrollers
Electrical programmable memory interface
Crystal oscillator frequency up to 8 MHz
Single 3V to 5V power supply
Up to 3 separate sets of 7-DIGIT Display Sets
3 sets of user defined 64-bit arithmetic multiplication factor
Software programmable serial data bit mask and sign
polarity mask
3 different sets of user selected data sample averaging with
up to maximum of 128X sampling
Optional 13-function user configurable hardware selection
switches
Automatic zero level shifting during power-on-reset
Automatic zero level overwrite feature
Adjustable decimal point placement with trailing digit
blanking
External 1K EEPROM memory for easy change of factory
settings
Sleep mode with Auto Power-On-Reset.
Easy setup of calibration and system setup parameters
No software programming required
PC Interface Software provided for Calibration and Setup
modes
©
2001 Advanced Linear Devices, Inc., 415 Tasman Drive, Sunnyvale, California 94089-1706, Tel: (408) 747-1155, Fax: (408) 747-1286
12/01
http://www.aldinc.com
1 of 20
ALD523D
PRODUCT APPLICATIONS
Embedded (up to ± 6½ -digit) digital panel meter
Customized/specialized instrument display
High precision DC voltage meters
Dedicated precision monitors
High resolution A/D converter with display
High accuracy and low noise weigh scale systems
Multifunction precision measurement instruments
Serial binary input to decimal/character display converter
Portable battery operated display systems
.
PRODUCT ORDERING INFORMATION
OPERATING TEMPERATURE RANGE
*
0
o
C to +70
o
C
28-Pin Plastic DIP Package
(PDIP)
0
o
C to +70
o
C
28-Pin Small Outline Package
(SOIC)
ALD523DPH
ALD523DSH
*: Contact factory for industrial temperature range
ALD523D PIN CONFIGURATIONS
CALIBRATED REFERENCE (MODE-A)
ALD523D
1
COUT
2 SDA
3 S1/SCL
4 B1/D4
5 B2/D5
6 DSA1/D6
7 DSA2/D7
+
8 V
9 XTAL2
10 XTAL1
11 COUT
12 CAL
13 PWRCS
14 CS
S3/RS 28
S2/EN 27
DATOUT 26
SCLK
DATIN
DEC2/D3
DGND
DEC1/D2
SEL1/D1
SEL0/D0
25
24
23
22
21
1 COUT
2 SDA
3 S1/SCL
4 B1/D4
5 B2/D5
6 DSA1/D6
7 DSA2/D7
+
8 V
9 XTAL2
10 XTAL1
11 COUT
12 CAL
13 PWRCS
14 CS
PH, SH PACKAGE
RATIOMETRIC (MODE-B)
ALD523D
S3/RS
S2/EN
DATOUT
SCLK
DATIN
Z/D3
DGND
28
27
26
25
24
23
20
19
DVCS 18
A 17
WP 16
B 15
22
M/D2 21
SEL1/D1 20
SEL0/D0 19
DVCS 18
A 17
WP 16
B 15
PH, SH PACKAGE
DISPLAY ONLY (MODE-C)
ALD523D
1 N/C
2 SDA
3 SCL
4 B1/D4
5 B2/D5
6 DSA1/D6
7 DSA2/D7
8 V
+
9 XTAL2
10 XTAL1
11 N/C
12 CAL
13 PWRCS
14 N/C
RS
EN
DATOUT
SCLK
DATIN
DEC2/D3
DGND
28
27
26
25
24
23
22
DEC1/D2 21
SEL1/D1 20
SEL0/D0 19
DVCS 18
N/C 17
WP 16
N/C 15
PH, SH PACKAGE
©
2001 Advanced Linear Devices, Inc., 415 Tasman Drive, Sunnyvale, California 94089-1706, Tel: (408) 747-1155, Fax: (408) 747-1286
12/01
http://www.aldinc.com
2 of 20
ALD523D
GENERAL DESCRIPTION
The ALD523D is a Multifunction 7-Digit Serial Input
Display Module Controller designed to interface directly
to ALD500 or ALD500R integrating dual slope precision
analog processors as a chip set for building a high
precision and high accuracy analog-to-digital converter
system with auto zero and auto-polarity. The ALD523D
also functions as an universal serial input 7-digit display
module controller that interfaces to most popular industry
standard serial data formats from other microprocessors or
data converters. It is designed for easy setting of industry
standard Character Display Modules (CDM) such as 1-line
by 16-character or 2-line by 16-character LCD or VFD
display modules. The ALD523D is an enhanced version of
the ALD521D digital controller. The ALD523D functions
in three separate operating modes, namely calibrated
reference (mode-A), ratiometric (mode-B), and display
only (mode-C).
The ALD523D digital controller operates as a master
display module controller in either a stand-alone mode or
in an external microprocessor control mode. In the external
microprocessor control mode, the ALD523D can directly
interface with a PC under PC software control via a
standard parallel printer port. This external control mode
is managed by the Serial I/O Interface Logic inside the
ALD523D.
In the stand-alone mode, the ALD523D makes continuous
measurements, and includes all the necessary functions to
fully control a CDM. In the stand-alone mode, ALD523D
operates in conjunction with a 1K EEPROM chip to
preserve the setup parameters and arithmetic (calibration)
parameters of the ALD523D.
The setup and arithmetic parameters are uploaded to the
EEPROM via ALD523D Setup and Calibration PC
software (DVM523). The ALD523D communicates to the
EEPROM on a handshake protocol governed by the
EEPROM Memory Controller inside the ALD523D.
The ALD500/ALD500R dual slope precision analog
processors consist of on-chip digital control circuitry to
accept control inputs, integrating buffer amplifiers, analog
switches, and voltage comparators. It functions in four
operating phases, namely auto zero, integrate, de-integrate,
and integrator zero phases. At the end of a conversion, the
comparator output goes from high to low when the
integrator
crosses
zero
during
de-integration.
ALD500/ALD500R dual slope precision analog
processors also provide direct logic interface to
ALD523D.
The ALD523D implements the logic and timing for all the
four phases of the ALD500/ALD500R, namely auto zero,
integrate, de-integrate, and integrator zero phases in mode-
A and mode-B operations. These four phases are
governed by the Dual Slope A/D 4-Phase Controller inside
the ALD523D. The ALD523D operates from an external
clock or its internal oscillator circuit along with an external
crystal. The internal system clock of the ALD523D runs
at a frequency which can be selected at divide-by N (4, 8,
or 64) rate of the crystal (or external) clock frequency.
The ALD523D offers up to 3 display settings, known as
display sets, namely “DGS1”, “DGS2” and “DGS3”.
“DGS1” also has an optional hardware decimal point
setting mode, known as “DGS0”, which allows the user to
use hardware jumper switches to set decimal point
position. Each display set allows a full 7-digit decimal
number to be converted from a 16-bit to 32-bit serial
binary number using the Serial Binary To 6½-Digit
Decimal Converter inside the ALD523D. This 6½-digit
decimal number can also be scaled by a MULTIPLIER
number, and the result of the scaled number displayed on
the CDM through the Display Module Controller within
the ALD523D. Additional display parameters that can be
manipulated are: Digit Blanking, which allows user
selection of number of digits to display; Decimal Point
placement, which controls placement of decimal point, if
any. Up to 3 sets of display UNIT fields are available,
each with a combination of alphanumeric characters up to
8 characters long.
The ALD523D also features hardware control-input pins
for power down (PWRCS), integration time selection (S1,
S2 and S3), data sample averaging (DSA1 and DSA2),
digit blanking (B1 and B2), decimal point placement
(DEC1 and DEC2), zero offset (M and Z), and display set
selection (SEL0 and SEL1). When not used, or if no
control is desired, each of these optional pins are wired to
their respective desired logic state, either V
+
or Ground
(DGND), through pull-up or pull-down resistors. The
functions of the control-input pins are managed by the
Control Logic section in the ALD523D.
MODES OF OPERATIONS
The ALD523D functions in either single operating mode
or multiple operating modes, namely calibrated reference
(mode-A), ratiometric (mode-B), and display only (mode-
C). In the single operating mode, ALD523D operates in
one of the three modes of operation, either mode-A, mode-
B or mode-C. In the multiple operating modes, the
ALD523D can operate interchangeably in each of the three
©
2001 Advanced Linear Devices, Inc., 415 Tasman Drive, Sunnyvale, California 94089-1706, Tel: (408) 747-1155, Fax: (408) 747-1286
12/01
http://www.aldinc.com
3 of 20
ALD523D
different operating modes. This feature becomes useful
for applications that require multiple modes of operations
where up to three different types of measurements are
made and displayed.
I. CALIBRATED REFERENCE MODE (MODE-A)
The calibrated reference mode (mode-A) is primarily
intended for measurements against a calibrated reference
voltage. The reference voltage can either be internal or
external. In this mode, the ALD523D runs its internal
analog-to-digital controller to manage data conversion
from an analog-to-digital converter chip with calibrated
reference voltage such as the integrating dual slope
precision analog processors ALD500R. One of the
practical applications of utilizing this mode of operation is
a precision digital voltmeter system design (see the
Application Design Note-AN523DA).
In this mode, ALD500 can also be used instead of the
ALD500R, with an external voltage reference. The block
diagram of mode-A is shown in figure 1. See ALD523D
pin configuration and identification section for mode-A
pin layout and description.
1K
EEPROM
CHARACTER
DISPLAY
MODULE
(1-LINE)
OR
(2-LINES)
is shown in figure 2. See ALD523D pin configuration and
identification section for mode-B pin layout and
description.
1K
EEPROM
CHARACTER
DISPLAY
MODULE
(1-LINE)
OR
(2-LINES)
ALD523D
ALD500
ANALOG
INPUT
FUNCTIONS
SELECTORS
Figure 2. Ratiometric mode (mode-B) block diagram.
III. DISPLAY ONLY MODE (MODE-C)
The display only mode (mode-C) is primarily intended for
receiving a ready external serial binary data, converting
and processing the data, and showing the processed data
on the CDM. In this mode, the ALD523D runs its internal
display controller to manage, process, and display the
received serial binary data from a transmitting instrument
or device. One of the applications of utilizing this mode of
operation is an external interface to ALD MB1S precision
digital voltmeter system. The block diagram of mode-C is
shown in figure 3. See ALD523D pin configuration and
identification section for mode-C pin layout and
description.
1K
EEPROM
ALD523D
ALD500R
ANALOG
INPUT
FUNCTIONS
SELECTORS
Figure 1. Calibrated reference mode (mode-A) block
diagram.
EXTERNAL
INSTRUMENT
(SERIAL DATA)
ALD523D
CHARACTER
DISPLAY
MODULE
(1-LINE)
OR
(2-LINES)
II. RATIOMETRIC MODE (MODE-B)
The ratiometric mode (mode-B) is primarily intended for
measurements against a ratiometric reference voltage. In
this mode, the ALD523D runs its internal analog-to-digital
controller to manage data conversion from an analog-to-
digital converter chip such as the integrating dual slope
precision analog processors ALD500 with ratiometric
reference voltage.
One of the practical example
applications of utilizing this mode of operation is a
precision weigh scale system design (see the Application
Design Note-AN523DB). The block diagram of mode-B
FUNCTIONS
SELECTORS
Figure 3. Display only mode (mode-C) block diagram.
©
2001 Advanced Linear Devices, Inc., 415 Tasman Drive, Sunnyvale, California 94089-1706, Tel: (408) 747-1155, Fax: (408) 747-1286
12/01
http://www.aldinc.com
4 of 20
ALD523D
ALD523 SETUP AND CALIBRATION SOFTWARE
In the stand-alone mode, ALD523D operates in
conjunction with a 1K EEPROM chip to preserve the
setup and arithmetic (calibration) parameters of the
ALD523D. These parameters are utilized to fully control
the CDM and measurement functions. The parameters are
preset by the user through the ALD523D Setup and
Calibration PC software known as DVM523.EXE, and
later uploaded to the EEPROM via a standard parallel
printer port. See the ALD523D Setup and Calibration
User Guide (DVM523) for more details.
SELECTING AND CONFIGURING MODES OF
OPERATIONS
The three ALD523D modes of operations, namely mode-
A, mode-B, and mode-C are configured in the .CDS file
(see Table 1 of the ALD523D Setup and Calibration
Software User Guide), and are selected by means of user
selection of SEL0 and SEL1 control inputs of the
ALD523D. Each display set “DGSx” has an associated
mode parameter “Mx” which specifies the mode of
operation. Hence, “DGS1”, “DGS2”, and “DGS3” have 3
associated mode specifying parameters “M1”, “M2”, and
“M3”, respectively. Each “Mx” parameter can be preset to
either “Mode-A”, “Mode-B”, or “Mode-C”.
I. CALIBRATED REFERENCE MODE (MODE-A)
Mode-A can be selected by setting the nibble “M1”
parameter, or “M2” or “M3” of the byte “M2-M3”
parameter to an “A” (HEX) in the .CDS file. “M1”, “M2”,
and “M3” are the mode selection parameters associated
with “DGS1”, “DGS2”, and “DGS3” display sets,
respectively.
In mode-A or mode-B operation, the bit masking
“SMSK1” to “SMSK4” and the polarity bit masking
“SMSK5” to “SMSK8” parameters are not utilized.
However, this mode transmits a 24-bit serial word on pin
26, DATOUT. This 24-bit serial word consists of 23-bit
binary data with MSB as the first bit, LSB the 23
rd
bit,
followed by a sign bit as the last bit. The sign bit is a
logical “1” as a positive sign, and logical “0” as a negative
sign.
II. RATIOMETRIC MODE (MODE-B)
Mode-B can be selected by setting the nibble “M1”
parameter, or “M2” or “M3” of the byte “M2-M3”
parameter to an “B” (HEX) in the .CDS file.
When the ALD523D is powered up the first time or after
power-on-reset, a zero correction is automatically set by
zeroing out the reading. This automatic zero correction
feature can be manually overwritten by the Z switch (see
Table 5) at any time. The overwrite feature is embedded
to eliminate the long wait time at long integration time,
and add flexibility to perform zero correction at any time.
However, the faster the integration time set, the less the
wait time is needed to perform the automatic zero
correction (i.e. it takes typically from about 1 to 14
seconds to automatically zero out a reading for integration
time of 16.66 ms to 300 ms, respectively).
III. DISPLAY ONLY MODE (MODE-C)
Mode-C can be selected by setting the nibble “M1”
parameter, or “M2” or “M3” of the byte “M2-M3”
parameter to an “C” (HEX) in the .CDS file. In mode-C
operation, switches “S1”, “S2”, and “S3” are internally
disabled.
In mode-C operation, the ALD523D receives a maximum
serial word length of 32 bits in accordance to 32 serial
clock pulses, and processes a maximum of 21-bit serial
word plus 1 sign bit within this 32-bit serial word. This
21-bit serial word can be any 21-bit consecutive serial data
stream segment within the 32-bit serial clocks, as selected
by programming of the bit masks “SMSK1” through
“SMSK4”. The length of the received serial word is
governed by a DVCS signal. A transition of DVCS from
high to low state signals the start of the serial input data bit
stream clocking. A transition of DVCS from low to high
state stops the serial input data bit stream clocking.
After an external instrument or processor sets the DVCS to
logic 0, the DATIN terminal of the ALD523D is ready for
serial input data stream. The ALD523D reads the first bit
of the serial input data stream on DATIN and sends a
serial clock pulse on the SCLK as an acknowledge signal
to the external instrument or processor. Then the
ALD523D reads the second bit of the serial input data
stream and sends out a second SCLK clock pulse. This
serial data reading and clocking process continues until
DVCS is set to high state or until a maximum of 32 serial
input data bits have been read. The serial clock SCLK
consists of a low to high transition followed by a high to
low transition.
The maximum converted decimal number from this 21-bit
binary data plus sign bit is
±
9999999, when a suitable
multiplier and an appropriate conversion factor are used.
The sign bit is defined as logic “0” as a positive sign, and
logic “1” as a negative sign. Alternatively, the sign bit
©
2001 Advanced Linear Devices, Inc., 415 Tasman Drive, Sunnyvale, California 94089-1706, Tel: (408) 747-1155, Fax: (408) 747-1286
12/01
http://www.aldinc.com
5 of 20
ALD523D
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